WTB Vulpine 700 X 40mm Tires: Getting Rolling

WTB Vulpine 700 X 40mm Tires: Getting Rolling – by Guitar Ted

WTB 700 x 40 Vulpine tires in the black wall SG2 type.
WTB’s new 700 x 40mm Vulpine SG2 tires

WTB recently announced the new size of the Vulpine, a tire we tested here at Riding Gravel in the 36mm width previously. We really liked the speed, ride feel, and grip that this ‘on the skinny side’ gravel tire had. Not surprisingly, we hoped that WTB would opt to offer a wider version of this great tire. They have and we have it here for test and review, both in the Mid-West and in SoCal.

Stock image showing the Vulpine in the tan wall version
The 700c x 40mm Vulpine in the 60TPI tan wall

What It Is: The Vulpine comes in two flavors- The SG2 black wall and the skin wall, folding bead type casing with no puncture protection belt. The SG2 version gets a 120TPI casing and the skin wall version comes in a 60TPI casing. Both are tubeless ready, of course, and can be run with a tube if so desired. Following is a bit of description for the Vulpine 40mm tire from WTB’s website:

The Vulpine 40 delivers all-out speed with a nearly uninterrupted centerline tread that maximizes rolling efficiency while minimalist outer knobs provide high-speed cornering confidence and protect the tread from punctures. The increased volume of the Vulpine 40 improves comfort and reduces fatigue during the most challenging races and strengthens its versatility as a fast-rolling tire that promotes speed while allowing you to remain in complete control at any pace.

Notes On SG2 Protection: The SG2 puncture protection version has a belt that runs across from bead to bead on the carcass of the Vulpine. This belt has uniquely shaped, flat thread Nylon fibers which WTB claims will reduce the amount of rubber that would otherwise be between the round Nylon threads, if those were utilized for a puncture protection belt, which normally is the case. The flattened threads of Nylon not only increase puncture and cut protection, but allow the tire to be lighter, more supple, and in turn, feel better and be faster. Furthermore; WTB claims these flattened fibers aid with air retention in the SG2 type tires.

The skin wall version has WTB’s Light/Fast rolling design and uses the Dual DNA Rubber compound, like the SG2 version does. Otherwise it is a standard folding bead construction with WTB’s excellent TCS tubeless design bead and casing. The tan walled version runs $65.95 each and the black wall SG2 version is $76.95 each. All prices are USD.

 Image showing GT mounting a WTB Vulpine
The Vulpine proved to be a typical tubeless mount on the WTB CZR wheel set.

First Impressions & Mounting: Both Grannygear and I received the new Vulpine tires in the 40mm size. Grannygear got the standard casing, tan wall version. I received the black wall SG2 version. We both agreed that our first take was that these looked a bit less than 40mm sized casings. Otherwise, they are the expected quality we have come to be familiar with from WTB. Meaning, high quality finish and feel.

Now onto the Scales of Truth! Grannygear reported that the standard casing, tan wall 700 X 40mm Vulpines weighed in at 417/425 grams. The SG2’s weighed in at 454/458 grams. That’s pretty light for 40mm tires, but we will see why that is in a minute here.

Mounting the Vulpine tires proved to be your typical experience with WTB TCS tires, which is a predictably easy process that yields results in a satisfying way. I mounted my set on WTB CZR wheels (tested here) and Grannygear chose a set of Hunt wheels to mount his on. Grannygear’s wheel set has a 25mm inner rim width while my CZR’s are slightly narrower than that at 23 mm internal width.

Now one of us was a bit dissatisfied and one of us was okay with the results of mounting. Let me first explain a couple of things to put this into context. First, inner rim width influences measured tire width with air pressures remaining similar. Secondly, a puncture protection belt limits tire stretch and that is figured in to the design to some extent. So, for instance, if you make a tire and you want the consumer to get a 40mm tire, you account for stretch which will eventually get them there at 40mm or just beyond. So, you might sell a tire that initially measures just below 40mm, but will stretch to that or slightly wider.

The WTB 700 X 40mm Vulpine on a bike in an outdoor setting.
The SG2 Vulpine started out on the skinny side, but it has stretched.

All that to say that the SG2 tires initially measured 37.7mm immediately after mounting at 40psi on a 23mm internal width rim. After 24 hours this stretched to 38.5mm. Then after a few rides the tires measured out to be 39.55mm. So, as you can see I was a bit disappointed at first, but I think these will actually end up becoming a true 40mm tire by the end of the review, and especially if I swap to a wider internal rim width wheel set.

Grannygear saw 40+ millimeters right away. So, the standard casing was not restricted by the SG2 belt and seems to be right on the money for width out of the gate. We’ll see how it comes out after Grannygear gets a few rides in on them.

A yellow bike leaning up against a privacy fence.
The 700 X 40mm Vulpines on GT’s Twin Six Standard Rando.

So Far… The WTB Vulpine is said to be the “racer’s choice‘ by WTB. We like it too, though we aren’t what we’d consider to be “racers” these days. That said, we’ll be putting lots of miles on these and we expect to find that the 40mm Vulpines will be the “little bit extra” than what we found with the 36mm tires. More speed, more grip, and greater ride feel.

The initial widths were a bit concerning, but as our contact at WTB says, putting a puncture protection belt in a tire has its challenges. One of which is determining how the tire stretches compared to standard casing’s. At any rate, we’re confident that the SG2 will end up being a 40mm tire for most riders. You just have to give it time to get there.

In the “Checkpoint” update we hope to have reports from the Mid-West and So Cal to share and we will see if the wider Vulpine is “more” or if it is not quite what we had hoped for when we opinied for a wider Vulpine in the past.

For more on this tire and WTB’s other offerings see their website here: www.wtb.com

Note: WTB sent over the new 700c X 40mm Vulpine tires to Riding Gravel for test and review at no charge. We are not being bribed, nor paid, for this review and we will always strive to give our honest thoughts and views throughout.


Author: Guitar Ted

Guitar Ted hails from Iowa. Home of over 70,000 miles of gravel and back roads. An inaugural member of the Gravel Cycling Hall of Fame and Co-creator of Trans Iowa in late 2004- Guitar Ted has been at the forefront of the growth of gravel events and riding since then. Creator of Gravel Grinder News in 2008, he produced the premier calendar of gravel and back road events. GT joined forces with Riding Gravel in late 2014.

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4 thoughts on “WTB Vulpine 700 X 40mm Tires: Getting Rolling

    1. @Justin P – The Vulpine is built on a completely different sized casing, it would seem. The Resolute is rounder in profile, if that makes any sense to you. The Vulpine is a bit flatter where the rubber meets the road,

      In my opinion, the Resolute is a better tire all around, but the Vulpine seems to ride better (in the SG2 versions comparatively) and the Vulpine is faster on harder surfaces than the Resolute is. As things stand now with choices from WTB, I would probably still go with a Resolute for all around riding and for the slightly larger volume. A true 42-45mm Vulpine would perhaps have swayed me to choose a Vulpine, but WTB decided not to go that way this time.

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